Fuel additives?

[reidy]

hi guys, random question ..... fuel additlives are they worth bothering with ? I don't use redex as you have to use it every time you fill up for it to take effect (says it on the bottle) but I've used one shot additives before that are for use once every 5000 miles or so in my car before that have definitely made a difference but never used them in my bike,
was thinking of trying it in my bike but what findings have you guys found with them before?

cheers in advance :)

[squirrel_hunter]

Looking at your profile pic you have a Curvy like me. The only fuel additive I have used is higher octane fuel to prevent carb icing.

[andrewsmith]

No gain most of the year.

Winter: Super unleaded or silkolene pro-fst

[wideguy]

Looking at your profile pic you have a Curvy like me. The only fuel additive I have used is higher octane fuel to prevent carb icing.
Why would high octane fuel prevent icing?
I think they've eliminated icing here in the U.S. by adding 10% ethanol to most all of our gasoline.

[Superstokes92]

Super unleaded never seemed to do much during the winter in my curvy, now using silkolene pro-fst and works well.

[squirrel_hunter]

Why would high octane fuel prevent icing?

That I don't know. But what I do know is swapping from the Regular 95 to the Super 97 fixes the carb icing problem.

[andrewsmith]

It means the engine isn't scavenging as much, as its reducing efficiency of the burn.
It'll be denser in one compound which will stop it.

I know what SH is on about as I've tried it and it does work, but a lot does depend on the fuel quality. The big name forecourts (I.e: BP) that is the highest quality fuel and the supermarkets being the crap in short. Tesco fuels are the lowest quality, had too many issues with the 95 and had to fill with 97 from another forecourt to improve the fuel

[wideguy]

All I know about carb icing comes from aircraft training. A venturi causes pressure drop, which causes temperature drop. Vaporizing fuel causes additional temperature drop. If the ambient temperature and humidity are in the right range, the water in the incoming air freezes in the cold venturi. Water in the fuel would also freeze in the cold venturi. Aircraft fuel is carefully monitored for water in the fuel, but the solution to carb icing is carb heat.
Water free fuel will certainly help.

reidy, were you asking about fuel additives to prevent icing, or fuel additives to increase performance?

[yorkie_chris]

All snake oil unless your bike needs servicing. If that is the case, then service it.

If you suffer with carb icing add a small amount of isopropanol (main ingredient of proFST, and cheap) also allows a bit of water to get mixed and removed which may solve some running issues.

[embee]

Wideguy's icing description is good, and as YC says, a small percentage of isoproyl alcohol (IPA) will help. I believe the alcohol attaches to the water molecules and inhibits ice crystal formation.

Straight IPA can be had on ebay for very reasonable cost compared to the proprietary branded products. I'm not sure what the recommended dosage rate is, what does the FST recommend? I've read a thread elsewhere where someone had experimented and found 1% to be the minimum acceptable, so try 1 or 2%.

As for other additives, the only thing worth considering if absolutely necessary is some injector cleaner, it does work to some extent, but generally speaking with modern injectors and decent modern fuel the issues of injector plugging are rare these days.

Just use decent fuel, I tend to stick to Shell, BP etc where possible.

Don't use any additives in your engine oil, just use decent oil, it has all the additives needed already.

[johnnyrod]

Embee has the way of it. Redex is ye olde technology anyway, fien if you fancy decoking an aircooled 2-stroke